Color display having horizontal sub-pixel arrangements and layouts

ABSTRACT

A color display having horizontal sub-pizel arrangements and layouts is disclosed. The display can include a plurality of a sub-pixel group. The sub-pixel group can have a plurality of sub-pixels wherein each sub-pixel has a height along a vertical axis and a width along a horizontal axis. The width of each sub-pixel is greater in length than its height in the sub-pixel group. The display also includes a column driver coupled to each sub-pixel in a column and a row driver coupled to each sub-pixel in a row of the sub-pixel group. Each sub-pixel in the sub-pixel group is coupled to the row driver along the width of the sub-pixel.

RELATED APPLICATIONS

[0001] This application is a continuation-in-part of the following U.S.patent applications: U.S. patent application Ser. No. 09/628,122 (“the'122 appliction”), entitled “ARRANGEMENT OF COLOR PIXELS FOR FULL COLORIMAGING DEVICES WITH SIMPLIFIED ADDRESSING,” filed on Jul. 28, 2000,U.S. patent application Ser. No. 09/916,232 (“the '232 application”),entitled “ARRANGEMENT OF COLOR PIXELS FOR FULL COLOR IMAGING DEVICESWITH SIMPLIFIED ADDRESSING,” filed on Jul. 25, 2001, U.S. patentapplication Ser. No. 10/024,326 (“the '326 application”), entitled“IMPROVEMENTS TO COLOR FLAT PANEL DISPLAY SUB-PIXEL ARRANGEMENTS ANDLAYOUTS,” filed on Dec. 14, 2001, and U.S. patent application Ser. No.10/150,394 (“the '394 application”), entitled “ROTATBLE DISPLAY WITHSUB-PIEXL RENDERING,” filed on May 17, 2002, which are all herebyincorporated herein by reference.

[0002] This application is also related to the following co-pending U.S.patent applications: U.S. patent application Ser. No. ______, entitled“IMPROVEMENTS TO COLOR FLAT PANEL DISPLAY SUB-PIXEL ARRANGEMENTS ANDLAYOUTS FOR SUB-PIXEL RENDERING WITH SPLIT BULE SUB-PIXELS,” filed on______; U.S. patent application Ser. No. ______, entitled “IMPROVEMENTSTO COLOR FLAT PANEL DISPLAY SUB-PIXEL ARRANGEMENTS AND LAYOUTS FORSUB-PIXEL RENDERING WITH INCREASED MODULATION TRANSFER FUNCTIONRESPONSE,” filed on ______; and U.S. patent application Ser. No. ______,entitled “IMPROVEMENTS TO COLOR FLAT PANEL DISPLAY SUB-PIXELARRANGEMENTS AND LAYOUTS WITH REDUCED BLUE LUMINANCE WELL VISIBILITY,”filed on ______, which are all hereby incorporated herein by referenceand commonly owned by the same assignee of this application.

BACKGROUND

[0003] The present application relates to improvements to displaylayouts, and, more particularly, to improved color pixel arrangements.

[0004] Full color perception is produced in the eye by three-colorreceptor nerve cell types called cones. The three types of cones aresensitive to different wavelengths of light: long, medium, and short(“red”, “green”, and “blue”, respectively). The relative density of thethree differs significantly from one another. There are slightly morered receptors than green receptors. There are very few blue receptorscompared to red or green receptors.

[0005] The human vision system processes the information detected by theeye in several perceptual channels: luminance, chromanance, and motion.Motion is only important for flicker threshold to the imaging systemdesigner. The luminance channel takes the input from only the red andgreen receptors. In other words, the luminance channel is “color blind.”It processes the information in such a manner that the contrast of edgesis enhanced. The chromanance channel does not have edge contrastenhancement. Since the luminance channel uses and enhances every red andgreen receptor, the resolution of the luminance channel is several timeshigher than the chromanance channels. Consequently, the blue receptorcontribution to luminance perception is negligible. The luminancechannel thus acts as a resolution band pass filter. Its peak response isat 35 cycles per degree (cycles/°). It limits the response at 0 cycles/°and at 50 cycles/° in the horizontal and vertical axis. This means thatthe luminance channel can only tell the relative brightness between twoareas within the field of view. It cannot tell the absolute brightness.Further, if any detail is finer than 50 cycles/°, it simply blendstogether. The limit in the horizontal axis is slightly higher than thevertical axis. The limit in the diagonal axes is significantly lower.

[0006] The chromanance channel is further subdivided into twosub-channels, to allow us to see full color. These channels are quitedifferent from the luminance channel, acting as low pass filters. Onecan always tell what color an object is, no matter how big it is in ourfield of view. The red/green chromanance sub-channel resolution limit isat 8 cycles/°, while the yellow/blue chromanance sub-channel resolutionlimit is at 4 cycles/°. Thus, the error introduced by lowering thered/green resolution or the yellow/blue resolution by one octave will bebarely noticeable by the most perceptive viewer, if at all, asexperiments at Xerox and NASA, Ames Research Center (see, e.g., R.Martin, J. Gille, J. Larimer, Detectability of Reduced Blue Pixel Countin Projection Displays, SID Digest 1993) have demonstrated.

[0007] The luminance channel determines image details by analyzing thespatial frequency Fourier transform components. From signal theory, anygiven signal can be represented as the summation of a series of sinewaves of varying amplitude and frequency. The process of teasing out,mathematically, these sine-wave-components of a given signal is called aFourier Transform. The human vision system responds to thesesine-wave-components in the two-dimensional image signal.

[0008] Color perception is influenced by a process called “assimilation”or the Von Bezold color blending effect. This is what allows separatecolor pixels (also known as sub-pixels or emitters) of a display to beperceived as a mixed color. This blending effect happens over a givenangular distance in the field of view. Because of the relatively scarceblue receptors, this blending happens over a greater angle for blue thanfor red or green. This distance is approximately 0.250 for blue, whilefor red or green it is approximately 0.12°. At a viewing distance oftwelve inches, 0.25° subtends 50 mils (1,270μ) on a display. Thus, ifthe blue pixel pitch is less than half (625μ) of this blending pitch,the colors will blend without loss of picture quality. This blendingeffect is directly related to the chromanance sub-channel resolutionlimits described above. Below the resolution limit, one sees separatecolors, above the resolution limit, one sees the combined color.

BRIEF DESCRIPTION OF THE DRAWINGS

[0009] The accompanying drawings, which are incorporated in, andconstitute a part of this specification illustrate implementations andembodiments of the invention and, together with the description, serveto explain principles of the invention.

[0010]FIG. 1 shows a repeat cell of six sub-pixels wherein thesub-pixels are laid out length-wise horizontally.

[0011]FIG. 2A through 2F depicts various embodiments of sub-pixelarrangements laid out in a horizontal fashion.

[0012]FIG. 3 shows a novel six sub-pixel repeat cell arrangement for apanel display.

[0013]FIG. 4 shows one embodiment of an arrangement of sub-pixels laidout in a horizontal fashion connected to column and row drivers.

[0014]FIG. 5 shows one embodiment of a set of TFT connections to asub-pixel arrangement.

[0015]FIGS. 6A and 6B show two separate embodiments of an arrangement ofsub-pixels comprising unique connections of its TFTs to the columndrivers.

[0016]FIGS. 7 and 8 show two separate embodiments of a TFT connectionfor a novel eight sub-pixel repeat cell arrangement.

[0017]FIG. 9 shows one possible dot inversion scheme for one embodimentof an arrangement laid out in a horizontal fashion.

[0018]FIGS. 10 and 11 depict two different embodiments of TFTconnections to driver without use of crossovers for the novel eightsub-pixel repeat cell arrangement.

[0019]FIGS. 12A, 12B, and 12C depict various embodiments of a systemarchitecture for panels comprising arrangements of sub-pixels laid outin a horizontal fashion.

DETAILED DESCRIPTION

[0020] Reference will now be made in detail to implementations andembodiments of the invention, examples of which are illustrated in theaccompanying drawings. Wherever possible, the same reference numberswill be used throughout the drawings to refer to the same or like parts.

[0021] Sub-Pixel Arrangements

[0022] In FIG. 1, an arrangement of sub-pixel emitters 100 is shown,comprising a six sub-pixel repeat cell comprised of three colors. Thissix sub-pixel repeat cell was substantial shown in the '232application—however, the sub-pixels in FIG. 1 are laid out lengthwisealong the horizontal axis. For example, the horizontal width of thesub-pixels can be greater in length than the vertical height of thesub-pixels. In one embodiment, sub-pixels 106 are blue colored, whilesub-pixels 102 and 104 could be assigned either red or green colored,respectively. In another embodiment, sub-pixels 106 could be assignedthe color green, while sub-pixels 102 and 104 are either red or bluecolored, respectively. In yet another embodiment, sub-pixels 106 couldbe assigned the color red, while sub-pixels 102 and 104 are either greenor blue colored, respectively. Other color variations can implemented aswell, which are different from red, green and blue,such that the colorgamut of the resulting arrangement creates a useable display from auser's standpoint.

[0023] As shown in FIG. 1, sub-pixels 102 and 104 are displayed in a“checkerboard” fashion—whereby the red and green sub-pixel subplanes aredisplayed 180 degrees out of phase. Such a checkerboard pattern has beenpreviously disclosed in the '232 application and in U.S. patentapplication Ser. No. 09/628,122 (“the '122 application”), entitled“ARRANGEMENT OF COLOR PIXELS FOR FULL COLOR IMAGING DEVICES WITHSIMPLIFIED ADDRESSING,” filed on Jul. 28, 2000, which is herebyincorporated herein by reference and is commonly owned by the sameassignee of this application and such a checkerboard arrangement issimilarly advantageous with the sub-pixels laid out in the horizontalaxis as in the vertical axis.

[0024] As was disclosed in the '394 application, an entire panelconstructed with the sub-pixels lengthwise in the vertical axis (e.g.,the vertical height having a greater length that the horizontal width)could be enabled in software to perform sub-pixel rendering when thepanel is physically rotated 90 degrees from the vertical—in essence,running the panel with all sub-pixels in the horizontal axis. Thisfeature enabled a single panel to perform sub-pixel rendering whiledisplaying images in either the landscape or portrait mode of operation.

[0025] It may be advantageous, however, to physically construct a panelwith all sub-pixels laid out length-wise along the horizontal axis(e.g., the vertical height having a smaller length than the horizontalwidth). In particular, with sub-pixels 106 assigned with the color blue,one advantage is that the blue stripe is moved from the vertical tohorizontal axis—thus, de-emphazing the presence of a contiguous bluestructure, which is more apparent to the human eye along the verticalaxis than it is along the horizontal axis. A vertical blue stripe, thus,tends to interfere with text readability and uniformity as text iscomprised mostly of vertical strokes. A similar advantage is alsopossible with sub-pixels 106 assigned the color green.

[0026] FIGS. 2A-2F depict several alternative embodiments of sub-pixelarrangements laid out in the horizontal axis. FIG. 2A show that thesub-pixels 106 are effectively twice the length along the horizontalaxis of sub-pixels 102 and 104. Such a choice of length for sub-pixel106 was previously disclosed in the '232 application along the verticalaxis. Also shown, sub-pixels 106 could be of smaller width along thevertical axis than sub-pixels 102 and 104. Such a choice for lengthalong the vertical axis is also disclosed in the related co-pendingapplications noted above.

[0027]FIGS. 2C and 2D depict the addition of a “black” pixel 108 that isdisclosed in the co-pending and commonly assigned U.S. patentapplication Ser. No. ______, entitled “IMPROVEMENTS TO COLOR FLAT PANELDISPLAY SUB-PIXEL ARRANGEMENTS AND LAYOUTS WITH REDUCED BLUE LUMINANCEWELL VISIBILITY,” filed on ______. Black pixel 108 could also bedeployed in a staggered fashion, as shown in FIG. 2D. FIGS. 2E and 2Fdepict the addition of a fourth color pixel 110 as was previouslydisclosed in U.S. patent application Ser. No. 10/243,094, entitled“IMPROVED FOUR COLOR ARRANGEMENTS OF EMITTERS FOR SUB-PIXEL RENDERING,”filed on Sep. 13, 2002, which is hereby incorporated herein by referenceand commonly owned by the same assignee of this application.

[0028]FIG. 3 depicts an alternative arrangement 300 of sub-pixelscomprising a 3×2 column/row repeat cell 302. One possible colorassignment for arrangement 300 has sub-pixels 106 as blue, sub-pixels102 as red, and sub-pixels 104 as green. This arrangement may beconsidered somewhat as placing the blue sub-pixel stripes on thehorizontal axis, even though each sub-pixel has its lengthwise edge onthe vertical axis. This arrangement further disperses the blue stripe bystaggering the placement of blue sub-pixels; while slightly altering thered/green checkerboard pattern somewhat by placing the red and greensubplanes partially 45 degrees out of phase thereby staggering the redand the green sub-pixels in a novel manner.

[0029] Circuit Architecture

[0030]FIG. 4 depicts a high level architecture diagram whereby oneexemplary sub-pixel arrangement 400 is laid out in the horizontalfashion described above and column drivers 402 and row drivers 404 areelectrically mated to arrangement 400.

[0031] For panels employing thin film transistors (TFTs) to actuate ordrive sub-pixels, FIG. 5 depicts one embodiment of a TFT layout for thebasic arrangement of FIG. 1. Each sub-pixel is connected to a columnline 502 and a row line 504. TFT 506, located at each sub-pixel,actuates or drives a sub-pixel according to signals that are resident onits connected row and column line.

[0032]FIGS. 6A and 6B depict two alternative embodiments of TFT layouts602 and 604 respectively. Each layout alters the location of the thirdcolumn line differently from that of FIG. 5. In FIGS. 6A and 6B, thethird column line is on the right or left of the second column ofsub-pixels respectively. In FIG. 6A, there is a crossover of the thirdcolumn line by the blue data going to the blue sub-pixel in the secondrow. In FIG. 6B, there are no data crossovers, which may minimizecrosstalk. In either case, aperture ratio may decrease to allow for theextra column line.

[0033]FIGS. 7 and 8 depict a layout for an arrangement 700 of sub-pixelscomprising a repeat cell 702 of eight sub-pixels. This repeat cell—withits various color assignments for sub-pixels 102, 104 and 106—is furtherdisclosed in co-pending and commonly assigned U.S. patent applications:U.S. patent application Ser. No. ______, entitled “IMPROVEMENTS TO COLORFLAT PANEL DISPLAY SUB-PIXEL ARRANGEMENTS AND LAYOUTS FOR SUB-PIXELRENDERING WITH SPLIT BULE SUB-PIXELS,” filed on ______ and U.S. patentapplication Ser. No. ______, entitled “IMPROVEMENTS TO COLOR FLAT PANELDISPLAY SUB-PIXEL ARRANGEMENTS AND LAYOUTS FOR SUB-PIXEL RENDERING WITHINCREASED MODULATION TRANSFER FUNCTION RESPONSE,” filed on ______,respectively. FIG. 7 shows this arrangement as laid out in a horizontalfashion. This octal grouping is unique in that it presents an extrastripe of sub-pixels 102. The TFT layout for this arrangement may beconstructed without adding TFTs (704) or without adding extra drivers(706), as shown in FIGS. 7 and 8 respectively.

[0034] With a color assignment of blue sub-pixels 106, red sub-pixels102 and green sub-pixels 104, it can be seen in FIG. 7 that the bluedata is sent to two blue sub-pixels through one TFT. There is acrossover of the red/green data line which may lead to some crosstalk.In FIG. 8, there are additional TFTs, but there are no crossovers.

[0035] In the various arrangements above embodied in an AMLCD panel, a“dot inversion” scheme may be employed to operate the panel. Both a 1×1and 2×1 dot inversion scheme have been previously discussed as suitable.In particular, a 2×1 dot inversion scheme may reduce crosstalk in someof these embodiments. In cases where there are two column linesadjacent, there may be two pixels that have the same polarity next toeach other. However, the intervening data line is of opposite polarity,so low crosstalk may still be achieved. As one example, FIG. 9 depicts adot inversion scheme for AMLCD panels having the arrangement of FIGS. 6Aand 6B.

[0036] To achieve substantially the same number of drivers with thedisplay utilizing octal repeat cell 702 as a display with a repeat cellshown in FIG. 1, it is possible to interconnect the two blue columns106. In a TFT array, this could be achieved with row or column metallines. In a passive display, on the other hand, there is typically onlythe itanium tin oxide ITO line and no easy way to add a crossover.Therefore, the crossover is made in the column driver or on the TAB.This might add some cost and complexity to the display.

[0037] To achieve a similar result without crossovers, FIGS. 10 and 11depict two layouts—1000 and 1100 respectively—for an arrangementsimilarly comprising the octal repeat cell of 702. The connections aremade on alternate sides in such a manner as to eliminate the crossover.In FIG. 10, the number of leads on right and left are in the ratio of2:1. The advantage of this connection is that the organization of datain column drivers is less complcxd. The connection pattern may berepeated to the bottom of the LCD.

[0038] In FIG. 11, the number of leads on each side in balanced. Theorder of data may be more complicated though. Left side data can proceedas follows: G1/R1, B3/4, R4/G4, etc., and the right side data canproceed as follows: B1/2, R2/G2, G3/R3, etc. This pattern may berepeated to the bottom of the display.

[0039] Thus, in displays where there are electrode connections on bothsides of the display, the number of connections to the column driver isreduced and the number of column drivers required is the same as for adisplay based on the repeat cell shown in FIG. 1. For mobile phone STNdisplays, which do not have any crossover metal capability, this canlead to cost reduction for displays incorporating octal repeat group702.

[0040] System Architecture

[0041]FIGS. 12A, 12B and 12C depict various system architectures 1210,1220, and 1230, respectively, that may vary depending upon the drivingscheme. As may be seen, these various embodiments differ in the locationof the sub-pixel rendering (SPR) logic location within the system. Thesystem architectures 1210, 1220, and 1230 of FIGS. 12A, 12B, and 12C,respectively, may apply to the various layouts shown in FIGS. 6-8. Thecomponents described in FIGS. 12A, 12B, and 12C can operate in a mannerdescribed in U.S. patent application Ser. No. 10/150,355, entitled“METHODS AND SYSTEMS FOR SUB-PIXEL RENDERING WITH GAMMA ADJUSTMENT,”filed on May 17, 2002, which is hereby incorporated herein by referenceand commonly owned by the same assignee of this application, to performsub-pixel rendering techniques with the sub-pixel arrangements disclosedherein.

[0042] While the invention has been described with reference toexemplary embodiments, various modifications or changes may be made andequivalents may be substituted for elements thereof without departingfrom the scope of the invention. In addition, many modifications may bemade to adapt a particular situation or material to the teachingswithout departing from the essential scope thereof. For example, some ofthe embodiments above may be implemented in other display technologiessuch as Organic Light Emitting Diode (OLED), ElectroLumenscent (EL),Electrophoretic, Active Matrix Liquid Crystal Display (AMLCD), PassiveMatrix Liquid Crystal display (AMLCD), Incandescent, solid state LightEmitting Diode (LED), Plasma Display Panel (PDP), and Iridescent.Therefore, it is intended that the invention not be limited to theparticular embodiments disclosed herein as the best mode contemplatedfor carrying out this invention, but that the invention will include allembodiments falling within the scope of the appended claims.

What is claimed is:
 1. A display comprising: a plurality of a sub-pixelgroup; said sub-pixel group comprising a plurality of sub-pixels whereineach sub-pixel having a height along a vertical axis and a width along ahorizontal axis, the width being greater in length than the height; acolumn driver coupled to each said sub-pixel in a column of thesub-pixel group; a row driver coupled to each said sub-pixel in a row ofthe sub-pixel group; and wherein each said sub-pixel of the sub-pixelgroup is coupled to said row driver along said width of said sub-pixel.2. The display as recited in claim 1 wherein said sub-pixel groupcomprises substantially a red sub-pixel and a green sub-pixelcheckerboard pattern.
 3. The display as recited in claim 2 wherein saidsub-pixel group comprises blue sub-pixels, each of said blue sub-pixelsis aligned substantially along a horizontal axis on said display.
 4. Thedisplay as recited in claim 1 wherein said sub-pixel group comprisessubstantially a red sub-pixel and a blue sub-pixel checkerboard pattern.5. The display as recited in claim 4 wherein said sub-pixel groupcomprises green sub-pixels, each of said green sub-pixels is alignedsubstantially along a plurality of horizontal axes on said display. 6.The display as recited in claim 1 wherein said display furthercomprises: a plurality of row lines,and wherein said plurality of asub-pixel group further comprises a plurality of rows of red and greensub-pixels and a plurality of rows of blue sub-pixels, wherein said redsub-pixels and said green sub-pixels substantially comprising acheckerboard pattern and said blue sub-pixels are aligned substantiallyalong a plurality of horizontal axes on said display; wherein every rowof sub-pixels are connected to a row line on alternating sides of saidpanel; and further wherein each two adjacent rows of blue sub-pixels arecoupled to one row line.
 7. The display as recited in claim 6 whereinsaid each two adjacent rows of blue sub-pixels are coupled to one rowline on a single side of said panel.
 8. The display as recited in claim6 wherein said each two adjacent rows of blue sub-pixels are couple to arow line on alternating sides of said panel.
 9. A display comprising: aplurality of a sub-pixel group; said sub-pixel group comprising aplurality of sub-pixels, wherein each said sub-pixel comprises one of agroup, said group comprising a first color sub-pixel, a second colorsub-pixel and a third sub-pixel; and wherein said sub-pixel groupfruther comprises two rows and four columns; wherein a first set of twonon-adjacent columns comprise four sub-pixels of a first color and asecond set of two non-adjacent columns comprise two sub-pixels of asecond color and two sub-pixels of a third color; and wherein furthersaid sub-pixels of said second color and said sub-pixels of said thirdcolor comprise a checkerboard pattern.
 10. The display as recited inclaim 9 wherein said first color comprises a green color and each saidsecond color and said third color comprise one of a group, said groupcomprising red and blue colors, respectively.
 11. The display as recitedin claim 9 wherein said first color comprises a red color and each saidsecond color and said third color comprise one of a group, said groupcomprising green and blue colors, respectively.
 12. The display asrecited in claim 9 wherein said first set of two non-adjacent columnsfurther comprise four sub-pixels of a first color wherein said foursub-pixels of a first color comprising a smaller area than saidsub-pixels of second color and said sub-pixels of said third color. 13.The display as recited in claim 9 wherein said display comprises anAMLCD display and said display applies a dot inversion scheme fordriving the sub-pixels.
 14. The display as recited in claim 13 whereinsaid dot inversion scheme is 1×1 dot inversion.
 15. The display asrecited in claim 13 wherein said dot inversion scheme is 2×1 dotinversion.
 16. A display comprising: a plurality of sub-pixelarrangements, each sub-pixel arrangement comprising a plurality ofsub-pixels such that each pixel is oriented on the display with a widthalong a horizontal axis greater in length than a height along a verticalaxis.
 17. The display of claim 16, wherein at least two of thesub-pixels in each sub-pixel arrangement receive a voltage of oppositepolarity.
 18. The display of claim 16, wherein each sub-pixelarrangement includes alternating red and green sub-pixels.
 19. A displaycomprising: a plurality of pixels, each pixel is oriented on the displaywith a width along a horizontal axis greater in length than a heightalong a vertical axis; and a controller to process input pixel data andto sub-pixel render the pixel data for output on the plurality of pixelson the display.
 20. The display of claim 19, wherein the plurality ofpixels include a red and green sub-pixel checker-board pattern.